DESCRIPTION (Applicant's abstract): This project will examine a model for school-based mental health service delivery for urban, low income, aggressive children, a highly vulnerable and under-served population. An ecological-mediational model for school-based mental-health services is proposed that specifies proximal school experiences as mediators of distal school-level factors (e.g., climate), across 4 ecological contexts related to childhood aggression: teacher, peer group, child, and family linkages to school. The ecological perspective emphasizes the need for least-restrictive, group-administered services, that are flexible and individualized across the multiple contexts for children's behavior, and that integrate into ongoing school routines and resources. The proposed school-based model, PALS (Parents and Peers as Leaders in School), proceeds in four phases: 1) engagement of key constituents in urban schools; 2) development of collaborative partnerships between classroom teacher, community parent, and mental health service provider; 3) systematic assessment of ecological contexts; and 4) delivery of empirical-based services. Subjects will be 300 children from approximately 170 classrooms in kindergarten, 2nd, and 4th grades from 15 inner-city Chicago public schools each serving low-income, African-American communities, diagnosed as Conduct Disorder or Oppositional Defiant Disorder (DSM-IV). In 10 schools, children (n=200) will be randomly assigned by classroom to PALS or clinic-based services. In the other 5 schools, children (n=100) will receive only clinic-based services to control for possible contamination effects in the schools receiving both conditions. The experimental design will be a 3 (PALS vs. same-school clinic-based services vs. other school clinic-based services) x 3 (pretest, posttest, 6 month follow-up). In Year 1, collaborative relationships and training of service providers will be initiated. Subject recruitment and service delivery will occur in Year 2. Years 2-3 will assess post-intervention and 6-month follow-up effects on: 1) children's, parents', and teachers' satisfaction with services, 2) children's rates of aggression and social functioning at school and home, and 3) need for additional or more intensive services. Results will contribute to an increased understanding of factors associated with the delivery of effective mental health services for children and families in urban, low income communities.